The sign of being bored for a pet bird? It can vary from bird to bird. Some birds will pull their own feather out when they are extremely bored or frustrated. Some birds will attempt to destroy stuff around them. From what I was told, it is recommended to rotate toys for your pet birds rather than putting too many toys in there at once. They can get bored of the same toys if they are available all the time.
Many species of pet birds also require human attention if they are kept alone. Some birds require at least an hour or so of your attention each day. If you are unable to provide the much needed attention, they can become depressed and it is unhealthy for them. It is a better idea to find them a companion if you don't have time to spare.
